Pathologic Nodal Staging Score for Bladder Cancer: A Decision Tool for Adjuvant Therapy After Radical Cystectomy

BackgroundRadical cystectomy (RC) with pelvic lymph node dissection (PLND) is the standard of care for high-risk non–muscle-invasive and muscle-invasive bladder cancer (BCa).ObjectiveTo develop a model that allows quantification of the likelihood that a pathologically node-negative patient has, indeed, no positive nodes.Design, setting, and participantsWe analyzed data from 4335 patients treated with RC and PLND without neoadjuvant chemotherapy at 12 international academic centers.InterventionsPatients underwent RC and PLND.Outcome measurements and statistical analysisWe estimated the sensitivity of pathologic nodal staging using a beta-binomial model and developed a pathologic (postoperative) nodal staging score (pNSS) that represents the probability that a patient is correctly staged as node negative as a function of the number of examined nodes.Results and limitationsOverall, the probability of missing a positive node decreases with the increasing number of nodes examined (52% if 3 nodes are examined, 40% if 5 are examined, and 26% if 10 are examined). The proportion of having a positive node increased proportionally with advancing pathologic T stage and lymphovascular invasion (LVI). Patients with LVI who had 25 examined nodes would have a pNSS of 80% (pT1), 88% (pT2), and 66% (pT3–T4), whereas 10 examined nodes were sufficient for pNSS exceeding 90% in patients without LVI and pT0–T2 tumors. This study is limited because of its retrospective design and multicenter nature.ConclusionsWe developed a tool that estimates the likelihood of lymph node (LN) metastasis in BCa patients treated with RC by evaluating the number of examined nodes, the pathologic T stage, and LVI. The pNSS indicates the adequacy of nodal staging in LN-negative patients. This tool could help to refine clinical decision making regarding adjuvant chemotherapy, follow-up scheduling, and inclusion in clinical trials.